Optical transceivers are used to transmit and receive optical signals for various applications including, without limitation, internet data center, cable TV broadband, and fiber to the home (FTTH) applications. Optical transceivers provide higher speeds and bandwidth over longer distances, for example, as compared to transmission over copper cables. The desire to provide higher speeds in smaller optical transceiver modules for a lower cost has presented challenges, for example, with respect to maintaining optical efficiency (power), thermal management, insertion loss, and manufacturing yield.
Optical transceiver modules generally include one or more transmitter optical subassemblies (TOSAs) for transmitting optical signals. One consideration in maintaining TOSA performance is backreflection of laser light. Backreflection can occur when, for example, laser energy incident to a laser cavity reflects back in the direction it originated from. To minimize or otherwise mitigate backreflection, TOSAs can include passive optics such as an optical isolator. Optical isolators allow the transmission of light in only one direction, and thus, prevent or otherwise mitigate backreflection.